Due to missing Nvidia drivers X11 failed to start, showing that big sad face...
When trying to find out what might be the problem, I realized that no text
consoles had been started.
At some later time I just "zapped the server" (how many users will know that?),
and I found virtual consoles then.

In the syslog I found (I suspect it might be related):
Sep 02 07:48:05 pc6 echo[4573]: Switch to tty1 Successfully
Sep 02 07:48:05 pc6 systemd[1]: Requested transaction contradicts existing
jobs: Transaction is destructive.
Sep 02 07:48:05 pc6 systemd-logind[1498]: Failed to start autovt@tty1.service:
Transaction is destructive.
Sep 02 07:48:05 pc6 display-manager[4499]: Shutting down service gdm..done